Last week, we walked you through the many mansions, predominately lost, along Millionaire’s Row on Fifth Avenue up to 59th Street. Most of this stretch has been converted into upscale luxury retail and corporate skyscrapers, but Millionaire’s Row continued northwards along Central Park, which opened in 1857. Though some have been lost, a significant number of these opulent Gilded Age mansions still stand within this more residential zone. The AIA Guide to New York Citycalls this area of Fifth Avenue from 59th Street to 78th Street the “Gold Coast,” and rightly so.